Pneumatic peck hammer



May 29, 1956 P. SHEPHERD PNEUMATIC PECK HAMMER Filed Dec. '7, 1955 R n r.

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W F i 4 w *l I a, m m w United States Patent PNEUMATIC PECK HAMMER Paul Shepherd, Bonner Springs, Kans.

Application December 7, 1953, Serial No. 396,650

3 Claims. (CI. 81-15) The present invention relates to fluid pressure percussive tools, and more particularly to a pneumatic peck hammer adapted to remove small dents from sheet metal structures such as automobile fenders and bodies.

An object of this invention is to provide a powerdriven, single impact peck hammer for use in metal working where it is necessary to work in locations not permitting the swinging of an ordinary hand-actuated harnmer.

Another object of the instant invention is to provide a pneumatic peck hammer that is relatively compact both in size and in weight so that the same may be handactuated and placed in use particularly in automobile body working where it is necessary to raise small indentations found on metal panels in otherwise inaccessible locations.

A still further object of the present invention is to provide a power driven hammer that may be attached to a source of power of the type usually found in automobile body shops.

With the above objects in view, the present invention contemplates an improved peck hammer including a pneumatic cylinder which may be hand-grasped and having an anvil block therein for striking a laterally extending peck pin, together with a reciprocable hammer piston for imparting hammer blows to the anvil block each time an air valve is opened by hand manipulation.

In the drawing:

Figure 1 is a perspective view of a pneumatic peck hammer made pursuant to my present invention.

Fig. 2 is a longitudinal, cross-sectional view thereof.

Fig. 3 is a transverse, cross-sectional view taken on line III-III of Fig. 2; and

Fig. 4 is a fragmentary, sectional view similar to Fig. 2 showing the front end of the hammer with the anvil block and the peck pin retracted.

An elongated cylinder 10, forming the main body portion of the peck hammer illustrated in the drawing, is preferably of such size as to be easily grasped by the hand of the operator. End closures in the nature of plugs 12 and 14 are threaded in the ends of the cylinder 10, the rear end closure or plug 12 being provided with a central bore 16 to present an air pressure inlet port and said bore 16 is partially threaded to receive an adaptor 18 serving to couple the cylinder with a source of air pressure (not shown), through the medium of a flexible hose 20. A control valve 22 is interposed between the hose or air-line 20 and valve 22 is in turn equipped with a finger actuator 24 that need merely be depressed in order to admit live air to the cylinder 10 through the bore 16 of plug 12.

The front end closure or plug 14 is provided with a lateral opening 26 that slidably receives a peck pin 28 having the outermost end thereof tapered into a point 30. The innermost end of the pin 28 is provided with a dome-shaped head 32 that is engaged by frusto-conical head 34 of an anvil block 36 and which serves the addi- 2,747,444 Patented May 29, 1956 tional purpose of limiting the extent of outward movement of the pin 28.

Anvil block 36 is reciprocable within the cylinder 10 toward and away from the plug 14 and is provided with an annular, outturned flange 38 that extends into a groove 40 formed in the cylinder 10. The annular, internal groove 40 of the cylinder 10 presents an outwardly facing shoulder 42 that is in opposed relationship to the innermost end 44 of the plug 14. The shoulder 42 and the plug end 44 present therefore, spaced stops for engagement by the flange 38 of block 36 to limit the extent of reciprocable movement of the latter on the longitudinal axis of the cylinder 10.

An elongated hammer piston 46 is also reciprocably mounted in the cylinder 10 for movement toward and away from the anvil 36. Piston 46 has a central cavity 48 that receives one end of a spring 50 attached to the piston 46 by means of a cross-pin 52. The opposite end of the spring 50 extends into the bore 16 of plug 12 and is provided with an enlarged end loop 54 for securing the spring 50 to the plug 12. Exhaust perforations 56 and 58 in the block 36 and in the block 14 respectively, are preferably in alignment on the longitudinal axis of the cylinder 10 and permit escape of air from the cylinder 10 under influence of the forwardly moving piston 46 as it is forced toward the anvil block 36.

In operation, when the operator grasps the cylinder '10 and moves the peck pin 28 against work 60, as shown in Fig. 4 of the drawing, pin 28 is forced inwardly and its dome-shaped head 32, acting slidably on the frustoconical head 34 of the anvil 36, shifts the latter to the innermost end of its path of travel where the flange 38 is in engagement with the shoulder 42. With the pin 28 and the anvil block 36 held in the position shown in Fig. 4 of the drawing, the operator depresses the actuator 24 of valve 22 to admit air under pressure to the cylinder behind the hammer piston 46, forcing the latter against the anvil 36 to impart a blow to the latter, thereby forcing the anvil 36 to the position shown in Fig. 2 where flange 38 engages the innermost end 44 of plug 14. Such outward movement of the anvil 36 toward the plug 14 forces the pin 28 outwardly and against the workpiece 60. Here again, by virtue of the frusto-conical configuration of the head 34, and the dome-shape of the head 32, anvil 36 slides relative to the pin 28 and the latter is easily forced outwardly against that face of work 60 which it engages.

As the piston hammer 46 moves under influence of the air pressure into striking engagement with the anvil 36 air in the cylinder 10 between the hammer 46 and the anvil 36 is not compressed but quickly evacuated from the cylinder 10 through the perforations S6 and 58.

Upon release of the actuator 24 of valve 22 to release the air pressure on piston 46, spring 50 acts to retract piston 46 toward the rearmost end of its path of travel as shown in the drawing. Air behind the piston 46 is exhausted from the cylinder 10 by virtue of the tubular nature of spring 50 and in this connection, it is to be pointed out that valves 22 are of such nature as to permit air flowing from the cylinder 10 behind the piston 46 to escape to the atmosphere.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. A single impact, pneumatic peck hammer comprising an elongated cylinder having a rear end closure provided with an air pressure inlet portion, and a front end closure provided with a laterally angled opening; a peck pin slidable in said opening; an anvil block having an inclined surface directly engageable with said pin and reciprocable in the cylinder longitudinally thereof toward and away from said front end closure for forcing the peck pin outwardly at an angle to the longitudinal axis of the cylinder; and a hammer piston reciprocable the cylinder longitudinally thereof toward and away from the anvil block for imparting hammer blows to the anvil block under influence of, air pressure admitted to the, said port. .7

2. A'singleimpact, pneumatic peck hammer. comprising an elongated cylinder having a rear end closure provided with an air pressure inlet port, a front end closure provided with a laterally angled opening, and an annular, internal groove adjacent the front end closure, presenting a pair of'opposed stop shoulders; a peck pin slidable in said opening; an anvil block having an inclined surface directly engageable' with said pin and reciprocable in the cylinder longitudinally thereof toward and away from said front endclosure for forcing-the peck pin outwardly at an angle to the longitudinal axis of the cylinder, said anvil block having an annular, outturned flange extending into said groove between said stop shoulders for limiting the. extent of reciprocable movenient of the anvil block; and a hammer piston reciprocable .in the cylinder longitudinally thereof toward and, away from the anvil block for imparting hammer blows to the anvil block under influence of air pressure admitted to .the said port. r

3. A single impact, penumatic peck hammer comprising an elongated cylinder having an internally threaded bore enlargement at each end thereof forming an outwardly-facing annular shoulder in the cylinder; a first perforated, externally threaded plug in one of said bore enlargements having an innermost annular edge facing the shoulder and spaced therefrom and provided with a laterally angled opening; a peck pin slidable in said opening and having a dome-shaped head on the innermost end thereof; aperforatedanvil block provided with a frusto-conical head having an inclined surface directly engageable with said head of the pin and reciprocable in the cylinder longitudinally thereof toward and away from said first plug for forcing the peck pin outwardly at an angle to the longitudinal axis of the cylinder, said anvil block having an annular, outtu'rned flange between the shoulder and said end of the first plug for] limiting the extent of reciprocable movement of the anvil block; a second externally threaded plug'in the other of said bore enlargements provided with an air pressure inlet port; a hammer piston provided with an elongated cavity on the longitudinal axis of the cylinder and facing the second plug, said hammer piston being reciprocable in the cylinder longitudinally thereof toward and away from the anvil block for imparting hammer blows to the anvil block under influence of air pressure admitted tothe said port; and a spring in the cylinder interconnecting the second plug and the hammer piston for yieldably' holding the latter biased toward the second plug. I

References Cited inthe file of this patent UNITED STATES PATENTS 2,004,459 Boehnke June 11, 1935 2,129,212 Hollenback Sept. 6, 1938 2,163,715 Stull June 27, 1939 2,483,626 Daku' Oct. 4, 1949 2,490,254 Casazza Dec. 6, 1949 2,655,825 Gendron Oct. 20, 1953 2,720,802 Geller Oct. 18, 1955 

